Electric heating apparatus



May 11,1926. 1,584,511

' R. H. CUNNINGHAM ELECTRIC HEATING APPARATUS Filed April 22. 1924 INVENTOR. Q/CHAED f lGU/V/V/NGHAM A TTORNEY Patented May 11,1'926 w I UNITED STATES, PATENT OFFICE.

RICHARD H. CUNNIN GHAM, OF NEW YORK, N. Y., ASSIGNOR TO DUBILIER CONDENSER & RADIO CORBORA'IION, A CORPORATION OF DELAWABE' ELECTRIC HEATING APPARATUS.

Application flled'april 22, 1924. Serial 1io.708,175.

This invention relates to improvements in Fromone of the terminals, such as the electric heating. apparatus, especially sad terminal 4, a conductor 6 leads to a bindirons for smoothing and pressing cloth and ing screw 7, which passes through a metallic garments. bar or strip 8, supported at its opposite ends An object of this invention is to provide and carrying in the middle a contact 9. This 60 an electrically heated ironso designed that contact 9 ordinarily rests upon a co-operatover-heatino thereof is automatically preingiecontact 10, carried by a thermostatic" vented, and. thereby all risk of 'damage member 11. This thermostatic member may either to the mechanism of the ironitself, or be a bar of aluminum bent or bowed to the cloth or garment, upon which the iron in the middle, and disposed adjacent the 0S is used, is obviated, preferably, the desired bar 8, and preferably beneath the same, result is secured by a thermostatically opand from this bar leads a conductor 12, erated circuit ,breaker, mounted upon the to one extremity of the coil 3, the opiron and working in conjunction with elecposlte extremity being connected to the trical elements to reduce the current flowing binding post 5. Ordinarily, current will 70 through the iron, when the temperature flow through the bar 8, the contacts 9 thereof reaches a pie-determined degree. and 10, the member 11, and the conductor This and other objects and advantages of 12, to the coil 3,. 1t if he iron Should the invention will appear from the followbecome too hot, the thermostatic member 11 2o i description, taken with the accompanywill be'nd downward to a. greater'extent in 75 ing drawings, and the novel features of the the H d le, nd thus separate the contacts invention are defined inthe claims ap- 9 an 10, 0 as to break the circuit at this pended hereto; but the disclosure is illus- P tra-tive only; and I may,of course, change Shown n F g'llre 1, an insulated terthe details of structure shown herein, withmal 1 may be located in the line of the 0 out departing from the essential principle COHdQCtOI r a purpose which will be of-operation. a described later.

On the drawings, The screw 7 passes through one end of the Figure 1 is aview mainly diagrammatic, bar n he adjacen end of the mem- Showmg a Portion of n electrically heated ber 11. It makes electrical contact with the I iron, in outline, with the heating coil therebill bu is insulated fronithe member 11 of, and the means for controlling the coil; y Sultable bushmg and I Suitable and washer '15; and the lower end of this screw Figure 2, is a side view of such an iron, is g g y nut 5 it can be partly in section, indi ating h th -t tightened. The opposite ends of the bar 8 00 shown in Figure 1 may be mounted u and member 11 are held together by similar such an iron in practice. parts; and the twobars, 8 and 11, are there- The same numerals identify the same fore ctri ally dlsconnected, so that curparts, throughout. rent passing to the screw 7, connected to the 40 7 As shown in the drawings, the iron com- Conductor 6 u flow from the ball 8 prises a h ll bod 1 on th t f hi h through the contacts 9 and 10 to reach the i d f t h dl 2; d ithi th thermostaticmember. As long as the conbody 1 is the usual heating coil 3, consisttacts 9 and 10 are together, the full current I ing of suitable wire, through which current flows through the heating coil 3. Between 45 1g a d; this coil being connected to a the bar 8 and the contact 13,,is a resistance binding post 4, which maybe taken as the element 17 one end of this resistance elepositive terminal; and another binding post ment being attached to the contact 18, and

5, to enable the coil 3 to'be conveniently the other being made fast under the head connected to a supply circuit. The'coil 3 of one of the screws 7. -This element is will, ofv course, be inside the body 1, and therefore in parallel with the contacts 9 and 1 the binding posts 4 and 5 are on the outside 10. VVhen-these contacts..are together, they of the same. 'Obviously, the terminals 4 and short circuit the resistance, but in case the 5 may be givenany shape which will'enable temperature of the iron rises to a point connection to be made in the readiest and which has been set as the limit, the action of 55 most convenient manner. the member 11, separating the contacts 9 the binding post 4, to the coil 3. Current can now flow through the coil' 3 as before, but on account of the resistance 17, it will be so reduced that the iron cannot be heated "to any higher point.

The contact point may be adjustably mounted in the member 11, and between this contact and the screw 7, joined to the conductor 6,1 may place a condenser 18, so that this condenser will be in multiple with the contacts 9 and 10. Upon the bar 8, over, the contact 9, is a cap 19, and over this cap is a mounting 20, secured by screws 21, to the iron to carryan adjusting screw 22. This screw may pass through a threaded opening in the mountin 20, and carry a binding nut 23, to engage t e top of this mounting, the screw having a milled head 24, so that it can be turned to press upon the cap 19, to a greater or less extent and thus enable the contact 9 to be carried higher or forced down to a lower position, so as to regulate the action of the thermostatic circuit breaker comprising the member 11, and the two contacts 9 and 10.

When the iron is in use, current ordinarily passes through the conductors 6 and 12, to reach the coil 3, and not only does the iron become as hot as is desired, but the thermostatic circuit breaker acts to separate the con-- tacts 9 and 10, and causes the current to flow through the resistance 17 to prevent further heating. The presence of the condenser 18 is necessary because the action of the ther mostatic circuit breaker is necessarily slow, and "when the contacts 9 and 10 are together, the condenser is always fully charged when the member 11 begins to move the contact 10 apart from the contact 9. Hence, if on account of the slow separation of the contacts 9 and 10, an arc should occur between these two contacts, owing to the continuance of the flow of current between these two contacts, before the resistance of the gap or space that is being made between them becomes great enough to interrupt the current entirely, the condenser will oppose the current to a sufficient extent to stop further flow of current across these two contacts, as soon as the member 11 begins to move the contact 10 away from the contact 9. Hence, any are that might be created between these contacts, is quenched at once.

From the foregoing, it will be apparent that the iron is very effectually controlled, and that by the use of the adjusting screw 2, the limiting temperature can be varied at will within permissible limits.

As indicated in Figure 2, the thermostatic member llwith the contact 10 is disposed inside the body 1 of the iron, and. the bar 8 together with the adjusting screw 22, and parts for mounting same, are on the outside of the iron; the contact 9 projecting into the body 1, through a suitable opening. The manner in which the thermostatic circuit breaker, the condenser, the resistance, and the adjusting screw 22 are assembled and disposed, with reference to the structure of the iron, is not material to the invention and the arrangement of such parts can, of course, be left to the designer, as my invention is concerned here solely with the combination described, and not the particular position which any part may occupy upon the iron carrying same. In fact, a heating iron is described above more for the purpose of explaining a specific device in connection with which my invention may be used. It can, of course, be utilized with any electrical appliance having a heating coil, the action of which is to be regulated.

Having described my invention, what I believe to be new and desire to secure and protect by Letters Patent of the United States is 1. The combination of a heating coil, a circuit breaker adapted to become operative when the heating of the coil has reached a pre-determined point, and a resistance connected to the coil, but normally shortcircuited by the circuit breaker.

2. The combination of a heating coil, a thermostatic circuit breaker comprising a pair of contacts, a condenser in multiple with said contacts, and a resistance normally short circuited by the circuit breaker, said circuit breakcr including a member becoming operative when the heating of the coil has reached a pre-determined degree, to separate the contacts and leave only the resistance in circuit with said coil.

3. The combination of a heating coil, a conducting bar, a contact carried by said bar, a cap upon said bar, a mounting adjacent said cap, an adjusting screw in said mounting, to bear upon said cap, a thermostatic member adjacent said bar and insulated therefrom, a second contact carried by said member to cooperate with the first contact, a resistance between said bar and said coil, and a condenser in multiple with said contacts, for the purpose set forth.

In testimony whereof 1 affix my signature.

RICHARD H. CUNNINGHAM. 

